Weichselian before 15,000 years B.P. in the Nordic countries: a symposium

The symposium, arranged in 1980 in Bergen, was the last in a series of three symposia on Weichselian events in the Scandinavian realm. Papers from the two earlier symposia were published in Boreas 8:2 (1979) and 9:4 (1980). Recent research has proved the history of the Scandinavian Ice Sheet to be more complicated than formerly thought. One problem relating to this research is dating beyond the limit of the radiocarbon method     

A continuous Eemian-Early Weichselian sequence containing pollen and marine fossils at Fjøsanger, western Norway

A complete interglacial cycle, named the Fjøsangerian and correlated with the Eemian by means of its pollen stratigraphy, is found in marine sediments just above the present day sea level outside Bergen, western Norway. At the base of the section there are two basal tills of assumed Saalian ( sensu lato ) age in which the mineralogy and geochemistry indicate local provenance. Above occur beds of marine silt, sand and gravel, deposited at water depths of between 10 and 50 m. The terrestrial pollen and the marine foraminifera and molluscs indicate a cold-warm-cold sequence with parallel development of the atmospheric and sea surface temperatures. In both environments the flora/fauna indicate an interglacial climatic optimum at least as warm as that during the Holocene. The high relative sea level during the Eemian (at least 30 m above sea level) requires younger neotectonic uplift. The uppermost marine beds are partly glaciomarine silts, as indicated by their mineralogy, drop stones and fauna, and partly interstadial gravels. The pollen indicates an open vegetation throughout these upper beds, and the correlation of the described interstadial with Early Weichselian interstadials elsewhere is essentially unknown. The section is capped by an Early Weichselian basal till containing redeposited fossils, sediments, and weathering products. Several clastic dikes injected from the glacier sole penetrate the till and the interglacial sediments. Radiocarbon dates on wood and shells gave infinite ages. Amino acid epimerization ratios in molluscs support the inferred Eemian age of the deposit. The Fjøsangerian is correlated with the Eemian and deep sea oxygen isotope stage 5e; other possible correlations are also discussed.     

An Early or Middle Weichselian sequence of proglacial, shallow marine sediments on western Svalbard

A 20 m thick shallow marine sequence, capped by a Late Weichselian lodgement till, is exposed for 200111 along the river in Linnedalen on the west coast of Svalbard. Five formations are recognized: Formation A, the oldest, consists of a shallow marine, proglacial fan, of channelized sandy turbidites, possibly fed from an ice-contact deposit. Formation B, a sequence of proglacial channels and ice-rafted debris, was formed during a small oscillation of the glacier. Formation C, a prograding, storm-dominated shoreline sequence, was formed during a sea level fall, assumed to be a result of glacio-isostatic uplift.
Formation D, a lodgement till formed during the last glacier advance in Linnedalen and formation E, a coarsening upwards sequence, were formed during the post-glacial sea level fall. The subtill sequence (fm. A, B and C) is dated to between 40,000BP (radiocarbon dates) and 120,000BP (thermoluminescence and amino acid D/L ratios). The glacier front was 10 km downvalley during deposition of formations A and B, relative to the present glacier terminus, and more than 12km during the late Weichselian maximum.     

The deglaciation of Sweden after 10,000 B.P.

A review is given of the past and present research on the deglaciation of Sweden north of the Middle Swedish End Moraines. Problems concerning the differences in the mode of deglaciation above and below the highest coastline and the activity of the ice are discussed. Dating of the deglaciation offers special problems. The clay-varve method and radiocarbon dating of the beginning of organic sedimentation in particular are discussed.     

The deglaciation of Scandinavia earlier than 10 000 B.P.: The 1978 Uppsala Symposium

The 1978 Uppsala Symposium was organized as a geste d'honneur to the memory of Otto Torell and his Ice-Age Theory, published a little more than a hundred years ago. The Symposium opened with a lecture on the development of the Ice-Age Theory, then four regional surveys of our present knowledge of the deglaciation pattern and chronology yielded new and somewhat controversial ideas about the melting of the Scandinavian Continental Ice, and more than forty individual research reports showed the dynamic scientific situation in Quaternary Geology in Norden. The Symposium and this issue of Boreas form part of the joint Nordic activity within the IGCP project entitled 'Quaternary Glaciations in the Northern Hemisphere'.     

Reservoir Quality Assessment of the Upper Permian Chhidru Formation,Salt and Surghar Ranges,Pakistan

The Late Permian succession of the Upper Indus Basin in northeastern Pakistan is represented by the carbonate-dominated Zaluch Group, which consists of the Amb, Wargal and Chhidru formations, which accumulated on the southwestern shelf of the Paleo-Tethys Ocean, north of the hydrocarbon-producing Permian strata of the Arabian Peninsula. The reservoir properties of the mixed clastic-carbonate Chhidru Formation (CFm) are evaluated based on petrography, using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD) techniques. The diagenetic features are recognized, ranging from marine (isopachous fibrous calcite, micrite), through meteoric (blocky calcite-I, neomorphism and dissolution) to burial (poikilotopic cement, blocky calcite-II-III, fractures, fracture-filling, and stylolites). Major porosity types include fracture and moldic, while inter- and intra-particle porosities also exist. Observed visual porosity ranges from 1.5%–7.14% with an average of 5.15%. The sandstone facies (CMF-4) has the highest average porosity of 10.7%, whereas the siliciclastic grainstone microfacies (CMF-3) shows an average porosity of 5.3%. The siliciclastic mudstone microfacies (CMF-1) and siliciclastic wacke-packestone microfacies (CMF-2) show the lowest porosities of 4.8% and 5.0%, respectively. Diagenetic processes like cementation, neomorphism, stylolitization and compaction have reduced the primary porosities; however, processes of dissolution and fracturing have produced secondary porosity. On average, the CFm in the Nammal Gorge, Salt Range shows promise and at Gula Khel Gorge, Trans-Indus, the lowest porosity.     

LICHENOMETRIC AGES OF THE LITTLE ICE AGE MORAINES ON KING GEORGE ISLAND AND OF THE LAST VOLCANIC ACTIVITY ON PENGUIN ISLAND (WEST ANTARCTICA)

The recently observed recession of glaciers on King George Island is associated with decades of climate warming in the Antarctic Peninsula region. However, with only 60 years of glaciological observations in the study area ages of the oldest moraines are still uncertain. The goal of the study was to estimate ages of lichen colonization on the oldest moraines of the Ecology and White Eagle Glaciers on King George Island and on the Principal Cone of Penguin Island volcano. The first lichenometric studies on these islands from the late 1970s used rates that had about four to five times slower Rhizocarpon growth rates. We re‐examined the sites and measured 996 thalli diameters to establish the surface ages. To estimate the age we used (1) long‐term Rhizocarpon lichen group growth rates established by authors using data from a previous lichenometric study on King George Island, and (2) previous data of lichen growth rates from other sub‐Antarctic islands. Our results suggest growth rates between 0.5 and 0.8 mm yr^–1. According to these rates the ages of the oldest moraine ridges are of the Little Ice Age and were colonized at the beginning of the twentieth century. The mid‐twentieth century age of lichen colonization on the historically active Penguin Island volcano might support the date of the last eruption reported by whalers in the end of the nineteenth and the beginning of the twentieth century.     

The distribution and abundance of seabirds off southwestern Greenland in autumn and winter 1988–1989

Ship-based surveys of seabirds were carried out off southwestern Greenland in the autumn of 1988 and winter of 1989. The results provide the first quantitative information on seabird distribution and numbers for single seasons and estimates for one particular area in winter. Some oceanographic habitat characteristics important for seabird distribution are described. In winter, high numbers of king eiders Somaleriaspectabilis , Brünnich's guillemots Urialomvia , glaucous gulls Larushyperboreus , Iceland gulls Larusglaucoides , great black-backed gulls Larusmarinus and black guillemots Cepphusgrylle were found in offshore habitats with heavy ice cover. An estimated 280,000 king eiders, 170,000 Brünnich's guillemots, 2,500 glaucous gulls, 7,000 Iceland gulls, 9,500 great black-backed gulls and 25,000 black guillemots were found in winter in an area west of Nuuk.     

Radiocarbon dating of marine shells, including a discussion of apparent age of Recent shells from Norway

General problems in determining and interpreting shell C¹⁴ dates are discussed: calculation methods, factors influencing primary activity (apparent age), and determination of contamination. It is concluded that shell dates are reliable when handled carefully. Measurements on ten shells, collected between 1898 and 1923 on the Norwegian coast, gave apparent ages from 340±75 to 550±80 years, indicating that apparent age is not a significant problem in dating of Norwegian shells.